I’m about to start panicking please help !!!

I had sex with my boyfriend without a condom and he didn’t finish inside me. But I’m so so so nervous I could end up pregnant..I’m on the pill and I take it perfectly but my emotions sometimes get out of wack and I don’t start my placebos till 13 days !!! I am so scared I’ve never been this anxious before. I understand there’s always a chance of pregnancy but how big of a chance ??????